Improving the electrochemical energy storage capacity of the renewable carbon derived from industrial tea waste

Abstract

Energy storage is gaining a vital role since the usage of portable electric/electronic devices and vehicles have been growing. Capacitors, called as electrochemical double layer capacitors or supercapacitors, find application on wide scale devices from mobile vehicles to huge electric vehicles with high energy and power densities, fast charge and discharge properties. Hence, energy is stored at the electrode-electrolyte interface, the electrode material forms the heart of this energy storage system. When the decreasing reserves of fossil resources and their environmental damages are considered, renewable 3-dimentional carbon could be a solution in the capacitor as carbon electrodes. Biomass-derived renewable carbon is cost-effective, abundant, sustainable, safety and environmentally friendly material. In this work, renewable carbon material was derived from industrial tea waste and three methods of graphitization, activation and heteroatom doping were implemented alltogether to develop the energy storage capacity of material. The structural ordering, surface area growth and capacitive contribution promoted the energy storage capacity to 25 F/g and high power density to 2.6 kW/kg of biowaste derived carbon.